Exhibits trace the development of atomic energy and weaponry, beginning with 4C BC Greek philosopher Democritus, who first proposed the existence of tiny particles as fundamental building blocks. There are replicas of Fat Man and Little Boy, nicknames given the world's first two nuclear bombs, and a B-29 bomber similar to the planes that dropped them. A preponderance of displays are given over to the Cold War era of the 1950s to 80s. A theater offers two films: Ten Seconds That Shook the World (51min) chronicles the history of The Manhattan Project; The Virtually Cool Tour (35min) allows a look into research at Sandia National Laboratories. Rotating exhibits may include robotics, nuclear medicine or arms control.